Osteochondromas (osteocartilagenous exostoses) include solitary and multiple lesions. The multiple form is inherited but thought to be due to a loss of two tumor suppressor EXT 1 and 2 genes. Lesions sometimes develop after chemotherapy. Most tumors develop by enchondral ossification under a cartilage cap.
Diagnosis Osteochondromas are usually first noted as masses that are painful when injured during play. These lesions are usually pedunculated but may be sessile. They may grow to a large size. Osteochondromas are so characteristic in appearance that the diagnosis is made by conventional radiographs.
Solitary Osteochondromas Benign cartilagenous tumors are common in the metaphyses of long bones. They occur sporadically and present as a mass, often about the knee. Presentations in the spine may be associated with neurologic dysfunction.
Multiple Osteochondromas The common multiple form is more common in boys. Multiple lesions about the wrist and ankle often cause progressive deformity. Others may cause valgus deformities about the knee.
Management depends on the location of the tumor.
Pain is the common indication for removal. Often several lesions are removed in one operative setting. Complications of excision include peroneal neuropraxia, arterial lacerations, compartment syndromes, and pathologic fracture.
Valgus knee can be managed by medial femoral or tibial hemistapling in late childhood.
Limb length inequality may require correction by an epiphysiodesis.
Wrist deformities result from growth retardation and bowing of the distal ulna. Management of these deformities is complex and controversial. Studies in adults show suprisingly little pain and functional disability, considering the magnitude of the deformity and the unsightly appearance.
Ankle deformities result from growth retardation of the distal fibula, producing ankle valgus. Studies in adults show significant disability and suggest that prevention or correction of tibiotalar valgus should be undertaken in late childhood or adolescence. Consider resecting the osteochondroma and performing an opening wedge osteotomy of the distal tibia. When identified in childhood, consider placing a medial malleolar screw to prevent excessive deformity. Deformities are often complex, and operative correction must be individualized.
Prognosis Very rarely, malignant transformation to chondrosarcoma occurs during adult life. This transformation is most common in solitary lesions, usually from lesions involving flat bones, and occurs about two decades earlier than primary chondrosarcomas. Most tumors are low grade. Because the transformation is very rare, prophylactic removal of exostoses is not appropriate.
These cartilage tumors are located within bone. They are common in the phalanges and long bones and increase in frequency during childhood. They produce the classic characteristic of cartilage tumors of speckled calcification within the lesion.
Types There are several different types of enchondromas.
Solitary lesions occur in the hands and feet. Removal and grafting is indicated if the lesions cause disability.
Ollier disease is a generalized disorder with cartilagenous enchondromas as one feature. Children with Ollier disease often have limb shortening and varus deformities involving one side of the skeleton. About one-fourth develop chondrosarcoma in adult.
Maffucci syndrome is a disorder with subcutaneous hemangiomatas and multiple enchondromas. Malignant transformation is not uncommon in adult life.
This is a primary bone tumor that occurs mostly about the knee during the second decade. The radiographic appearance is often characteristic with an eccentric position, a sclerotic rim with lobulated margins, and prominent septa. Manage with local resection and grafting.
These uncommon tumors occur in the epiphysis of bones often during adolescence. They occur in the upper humerus, femur, and tibia. They can be confused with infection or arthritis. They are aggressive and prone to recur. Treat by thorough curettage and possibly cryotherapy or phenolization and bone grafting. Operative injury to the growth plate or articular cartilage is due to the juxtaarticular location. Anticipate local recurrence in about 20% of lesions.
Dysplasia Epiphysialis Hemimelica
Dysplasia epiphysialis hemimelica (Trevor disease) is a cartilagenous tumor that arises from the growth plate or articular cartilage. The sites of involvement are the distal tibia and the distal femur. Lesions often involve one side of the epihysis and may show multilevel involvement in the same limb. The diagnosis is often difficult early on, as the lesion is primarily cartilagenous and poorly imaged with conventional radiographs. MRI is helpful in showing the extent of the tumor and separating the lesion from the normal epiphysis or joint cartilage. Excise extraarticular lesions. Remove intraarticular lesions and correct secondary deformity with an osteotomy as necessary. Recurrence of the tumor is common, due to its periarticular location and extensive involvement of adjacent bone. Multiple resections throughout childhood are often necessary.